RPGMemes

I don't know PBTA well but I believe so.

Basically, every scene and character can have 'aspects', which are things that are true about them. They're free form. Sometimes they're just there, like if you're in a bar it might have "Bubbling with drunk banter" or "Loud Pop Punk Soundtrack". Aspects can then affect what makes sense in the scene. "Loud Pop Punk" can make it easier to move without being heard, but harder to make a speech because no one can hear you, for example.

You can also explicitly create aspects. Turn off the jukebox and the aspect might change to "Weirdly Quiet Bar" or whatever. In a fight, you can use the "create an advantage" move. That's for stuff that isn't about taking them out of the conflict right now, but setting things up. Like pushing them off balance, disarming them, screaming "LOOK! A DISTRACTION!" whatever. If the roll comes out if your favor, you can create an aspect that's true and can also be invoked for a numeric bonus on a dice roll. So if you pants the guy you're fighting, he can't run full speed to chase you because his pants are down. You can also invoke that if you want to kick his ass, for a bonus on the dice roll.

These are all free form and it's up to the group to decide what it actually means. Most groups probably wouldn't let you invoke "I'm literally on fire!!" as a bonus if you're trying to sneak through a crowd.

Typically, as I understand it, you're either trying to take them out of the fight or trying to create advantages for side of the conflict. On a dramatic success on trying to take someone out, you can also create a small advantage.